Gas Laws
Boyle’s Law relates pressure and volume at constant temperature. What happens to the pressure if volume doubles?
Pressure halves (inverse relationship)
How much energy is required to heat 80 grams of water from 26oC to 48oC?
7.3x103 J
If 3.47mol of an ideal gas has a pressure of 2.85atm and a volume of 65.73L, what is the temperature of the sample? Give answer in Kelvin
658 K
What is the frequency of electromagnetic radiation having a wavelength of 2.1x10-7 m?
1.428x1015 s-1
A 3.0 L gas at 25°C expands to 6.0 L. What must happen to temperature (in Kelvin) if pressure is constant?
It must double (Charles’ Law: V ∝ T)
In a coffee-cup calorimeter, 100.0 g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6oC and the water was originally at 24.6oC. After the reaction, the temperature of both substances is 31.3oC. Was the reaction exothermic or endothermic? Explain.
Exothermic, the temperature decreased from 44.6oC to 31.3oC indicating energy was released by the HCl.
An unknown gas with a mass of 205 g occupies a volume of 20.0 L at standard temperature and pressure. What is the molar mass of the gas?
230. g/mol
What is the wavelength (in nm) of electromagnetic radiation with a frequency of 4.95 x 1014 s-1?
606 nm
A gas collected over water at 25°C has a total pressure of 765 torr. The vapor pressure of water is 24 torr. What’s the gas’s partial pressure?
741 torr
In a coffee-cup calorimeter, 100.0 g of H2O and 100.0 mL of HCl are mixed. The HCl had an initial temperature of 44.6oC and the water was originally at 24.6oC. After the reaction, the temperature of both substances is 31.3oC. Calculate how much heat the water lost or gained in Joules.
2.80 x 103 J
What volume of O2 gas at 25oC and 1.04 atm is needed for the complete combustion of 5.53 grams of propane (C3H8)?
C3H8 + O2 → CO2 + H2O
14.7 L
A certain metal has a work function of 3.06x10-19 J. Light with a wavelength of 450 nm shines on the surface of the metal. What is the threshold frequency?
4.62x1014 s-1
Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values:
2CO2(g) + H2O(g) → C2H2(g) + 5/2O2(g)
C2H2(g) + 2H2(g) → C2H6(g) ΔH=-94.5 kJ
H2O(g) → H2(g) + 1/2O2 (g) ΔH=71.2 kJ
C2H6(g) + 7/2O2(g) → 2CO2(g) + 3H2O(g) ΔH=-283 kJ
ΔH=235.1 kJ
Of the following gases, which one has density of 0.906 g/L at 315 K and 1.16 atm?
(a) Ne
(b) Ar
(c) Kr
(d) Xe
(e) He
A) Neon
How many Joules of energy are contained in a photon with λ = 550 nm?
3.6x10-19 J
What volume of O2 gas at 25oC and 1.04 atm is needed for the complete combustion of 5.53 grams of propane (C3H8)?
C3H8 + O2 → CO2 + H2O
14.7 L
When 1.00 g of fructose, C6H12O6(s), is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 1.58 °C. If the heat capacity of the calorimeter and its contents is 9.90 kJ/°C, what is qrxn (in kJ/mol) for this combustion?
-2.82x103 kJ
Calculate the density (in g/L) of C4H10 at 25°C and a pressure of 750 mmHg
2.3 g/L
Calculate the wavelength (nm) of light emitted when a hydrogen atom relaxes from n = 6 to n = 2.
410 nm